1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
|
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>dtls: GnuTLS API Reference Manual</title>
<meta name="generator" content="DocBook XSL Stylesheets Vsnapshot">
<link rel="home" href="index.html" title="GnuTLS API Reference Manual">
<link rel="up" href="intro.html" title="GnuTLS API Reference Manual">
<link rel="prev" href="gnutls-ocsp.html" title="ocsp">
<link rel="next" href="gnutls-tpm.html" title="tpm">
<meta name="generator" content="GTK-Doc V1.33.1 (XML mode)">
<link rel="stylesheet" href="style.css" type="text/css">
</head>
<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
<table class="navigation" id="top" width="100%" summary="Navigation header" cellpadding="2" cellspacing="5"><tr valign="middle">
<td width="100%" align="left" class="shortcuts">
<a href="#" class="shortcut">Top</a><span id="nav_description"> <span class="dim">|</span>
<a href="#gnutls-dtls.description" class="shortcut">Description</a></span>
</td>
<td><a accesskey="h" href="index.html"><img src="home.png" width="16" height="16" border="0" alt="Home"></a></td>
<td><a accesskey="u" href="intro.html"><img src="up.png" width="16" height="16" border="0" alt="Up"></a></td>
<td><a accesskey="p" href="gnutls-ocsp.html"><img src="left.png" width="16" height="16" border="0" alt="Prev"></a></td>
<td><a accesskey="n" href="gnutls-tpm.html"><img src="right.png" width="16" height="16" border="0" alt="Next"></a></td>
</tr></table>
<div class="refentry">
<a name="gnutls-dtls"></a><div class="titlepage"></div>
<div class="refnamediv"><table width="100%"><tr>
<td valign="top">
<h2><span class="refentrytitle"><a name="gnutls-dtls.top_of_page"></a>dtls</span></h2>
<p>dtls</p>
</td>
<td class="gallery_image" valign="top" align="right"></td>
</tr></table></div>
<div class="refsect1">
<a name="gnutls-dtls.functions"></a><h2>Functions</h2>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="functions_proto_type">
<col class="functions_proto_name">
</colgroup>
<tbody>
<tr>
<td class="function_type">
<span class="returnvalue">void</span>
</td>
<td class="function_name">
<a class="link" href="gnutls-dtls.html#gnutls-dtls-set-timeouts" title="gnutls_dtls_set_timeouts ()">gnutls_dtls_set_timeouts</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">unsigned <span class="returnvalue">int</span>
</td>
<td class="function_name">
<a class="link" href="gnutls-dtls.html#gnutls-dtls-get-mtu" title="gnutls_dtls_get_mtu ()">gnutls_dtls_get_mtu</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">unsigned <span class="returnvalue">int</span>
</td>
<td class="function_name">
<a class="link" href="gnutls-dtls.html#gnutls-dtls-get-data-mtu" title="gnutls_dtls_get_data_mtu ()">gnutls_dtls_get_data_mtu</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<span class="returnvalue">void</span>
</td>
<td class="function_name">
<a class="link" href="gnutls-dtls.html#gnutls-dtls-set-mtu" title="gnutls_dtls_set_mtu ()">gnutls_dtls_set_mtu</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<span class="returnvalue">int</span>
</td>
<td class="function_name">
<a class="link" href="gnutls-dtls.html#gnutls-dtls-set-data-mtu" title="gnutls_dtls_set_data_mtu ()">gnutls_dtls_set_data_mtu</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">unsigned <span class="returnvalue">int</span>
</td>
<td class="function_name">
<a class="link" href="gnutls-dtls.html#gnutls-dtls-get-timeout" title="gnutls_dtls_get_timeout ()">gnutls_dtls_get_timeout</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<span class="returnvalue">int</span>
</td>
<td class="function_name">
<a class="link" href="gnutls-dtls.html#gnutls-dtls-cookie-send" title="gnutls_dtls_cookie_send ()">gnutls_dtls_cookie_send</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<span class="returnvalue">int</span>
</td>
<td class="function_name">
<a class="link" href="gnutls-dtls.html#gnutls-dtls-cookie-verify" title="gnutls_dtls_cookie_verify ()">gnutls_dtls_cookie_verify</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<span class="returnvalue">void</span>
</td>
<td class="function_name">
<a class="link" href="gnutls-dtls.html#gnutls-dtls-prestate-set" title="gnutls_dtls_prestate_set ()">gnutls_dtls_prestate_set</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">unsigned <span class="returnvalue">int</span>
</td>
<td class="function_name">
<a class="link" href="gnutls-dtls.html#gnutls-record-get-discarded" title="gnutls_record_get_discarded ()">gnutls_record_get_discarded</a> <span class="c_punctuation">()</span>
</td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect1">
<a name="gnutls-dtls.other"></a><h2>Types and Values</h2>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="other_proto_type">
<col class="other_proto_name">
</colgroup>
<tbody>
<tr>
<td class="define_keyword">#define</td>
<td class="function_name"><a class="link" href="gnutls-dtls.html#GNUTLS-COOKIE-KEY-SIZE:CAPS" title="GNUTLS_COOKIE_KEY_SIZE">GNUTLS_COOKIE_KEY_SIZE</a></td>
</tr>
<tr>
<td class="datatype_keyword"> </td>
<td class="function_name"><a class="link" href="gnutls-dtls.html#gnutls-dtls-prestate-st" title="gnutls_dtls_prestate_st">gnutls_dtls_prestate_st</a></td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect1">
<a name="gnutls-dtls.description"></a><h2>Description</h2>
</div>
<div class="refsect1">
<a name="gnutls-dtls.functions_details"></a><h2>Functions</h2>
<div class="refsect2">
<a name="gnutls-dtls-set-timeouts"></a><h3>gnutls_dtls_set_timeouts ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span>
gnutls_dtls_set_timeouts (<em class="parameter"><code><a class="link" href="gnutls-gnutls.html#gnutls-session-t" title="gnutls_session_t"><span class="type">gnutls_session_t</span></a> session</code></em>,
<em class="parameter"><code>unsigned <span class="type">int</span> retrans_timeout</code></em>,
<em class="parameter"><code>unsigned <span class="type">int</span> total_timeout</code></em>);</pre>
<p>This function will set the timeouts required for the DTLS handshake
protocol. The retransmission timeout is the time after which a
message from the peer is not received, the previous messages will
be retransmitted. The total timeout is the time after which the
handshake will be aborted with <a class="link" href="gnutls-gnutls.html#GNUTLS-E-TIMEDOUT:CAPS" title="GNUTLS_E_TIMEDOUT"><code class="literal">GNUTLS_E_TIMEDOUT</code></a>.</p>
<p>The DTLS protocol recommends the values of 1 sec and 60 seconds
respectively, and these are the default values.</p>
<p>To disable retransmissions set a <em class="parameter"><code>retrans_timeout</code></em>
larger than the <em class="parameter"><code>total_timeout</code></em>
.</p>
<div class="refsect3">
<a name="gnutls-dtls-set-timeouts.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>session</p></td>
<td class="parameter_description"><p>is a <a class="link" href="gnutls-gnutls.html#gnutls-session-t" title="gnutls_session_t"><span class="type">gnutls_session_t</span></a> type.</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>retrans_timeout</p></td>
<td class="parameter_description"><p>The time at which a retransmission will occur in milliseconds</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>total_timeout</p></td>
<td class="parameter_description"><p>The time at which the connection will be aborted, in milliseconds.</p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
<p class="since">Since: 3.0</p>
</div>
<hr>
<div class="refsect2">
<a name="gnutls-dtls-get-mtu"></a><h3>gnutls_dtls_get_mtu ()</h3>
<pre class="programlisting">unsigned <span class="returnvalue">int</span>
gnutls_dtls_get_mtu (<em class="parameter"><code><a class="link" href="gnutls-gnutls.html#gnutls-session-t" title="gnutls_session_t"><span class="type">gnutls_session_t</span></a> session</code></em>);</pre>
<p>This function will return the MTU size as set with
<a class="link" href="gnutls-dtls.html#gnutls-dtls-set-mtu" title="gnutls_dtls_set_mtu ()"><code class="function">gnutls_dtls_set_mtu()</code></a>. This is not the actual MTU
of data you can transmit. Use <a class="link" href="gnutls-dtls.html#gnutls-dtls-get-data-mtu" title="gnutls_dtls_get_data_mtu ()"><code class="function">gnutls_dtls_get_data_mtu()</code></a>
for that reason.</p>
<div class="refsect3">
<a name="gnutls-dtls-get-mtu.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody><tr>
<td class="parameter_name"><p>session</p></td>
<td class="parameter_description"><p>is a <a class="link" href="gnutls-gnutls.html#gnutls-session-t" title="gnutls_session_t"><span class="type">gnutls_session_t</span></a> type.</p></td>
<td class="parameter_annotations"> </td>
</tr></tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gnutls-dtls-get-mtu.returns"></a><h4>Returns</h4>
<p> the set maximum transfer unit.</p>
</div>
<p class="since">Since: 3.0</p>
</div>
<hr>
<div class="refsect2">
<a name="gnutls-dtls-get-data-mtu"></a><h3>gnutls_dtls_get_data_mtu ()</h3>
<pre class="programlisting">unsigned <span class="returnvalue">int</span>
gnutls_dtls_get_data_mtu (<em class="parameter"><code><a class="link" href="gnutls-gnutls.html#gnutls-session-t" title="gnutls_session_t"><span class="type">gnutls_session_t</span></a> session</code></em>);</pre>
<p>This function will return the actual maximum transfer unit for
application data. I.e. DTLS headers are subtracted from the
actual MTU which is set using <a class="link" href="gnutls-dtls.html#gnutls-dtls-set-mtu" title="gnutls_dtls_set_mtu ()"><code class="function">gnutls_dtls_set_mtu()</code></a>.</p>
<div class="refsect3">
<a name="gnutls-dtls-get-data-mtu.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody><tr>
<td class="parameter_name"><p>session</p></td>
<td class="parameter_description"><p>is a <a class="link" href="gnutls-gnutls.html#gnutls-session-t" title="gnutls_session_t"><span class="type">gnutls_session_t</span></a> type.</p></td>
<td class="parameter_annotations"> </td>
</tr></tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gnutls-dtls-get-data-mtu.returns"></a><h4>Returns</h4>
<p> the maximum allowed transfer unit.</p>
</div>
<p class="since">Since: 3.0</p>
</div>
<hr>
<div class="refsect2">
<a name="gnutls-dtls-set-mtu"></a><h3>gnutls_dtls_set_mtu ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span>
gnutls_dtls_set_mtu (<em class="parameter"><code><a class="link" href="gnutls-gnutls.html#gnutls-session-t" title="gnutls_session_t"><span class="type">gnutls_session_t</span></a> session</code></em>,
<em class="parameter"><code>unsigned <span class="type">int</span> mtu</code></em>);</pre>
<p>This function will set the maximum transfer unit of the transport
that DTLS packets are sent over. Note that this should exclude
the IP (or IPv6) and UDP headers. So for DTLS over IPv6 on an
Ethernet device with MTU 1500, the DTLS MTU set with this function
would be 1500 - 40 (IPV6 header) - 8 (UDP header) = 1452.</p>
<div class="refsect3">
<a name="gnutls-dtls-set-mtu.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>session</p></td>
<td class="parameter_description"><p>is a <a class="link" href="gnutls-gnutls.html#gnutls-session-t" title="gnutls_session_t"><span class="type">gnutls_session_t</span></a> type.</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>mtu</p></td>
<td class="parameter_description"><p>The maximum transfer unit of the transport</p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
<p class="since">Since: 3.0</p>
</div>
<hr>
<div class="refsect2">
<a name="gnutls-dtls-set-data-mtu"></a><h3>gnutls_dtls_set_data_mtu ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span>
gnutls_dtls_set_data_mtu (<em class="parameter"><code><a class="link" href="gnutls-gnutls.html#gnutls-session-t" title="gnutls_session_t"><span class="type">gnutls_session_t</span></a> session</code></em>,
<em class="parameter"><code>unsigned <span class="type">int</span> mtu</code></em>);</pre>
<p>This function will set the maximum size of the *unencrypted* records
which will be sent over a DTLS session. It is equivalent to calculating
the DTLS packet overhead with the current encryption parameters, and
calling <a class="link" href="gnutls-dtls.html#gnutls-dtls-set-mtu" title="gnutls_dtls_set_mtu ()"><code class="function">gnutls_dtls_set_mtu()</code></a> with that value. In particular, this means
that you may need to call this function again after any negotiation or
renegotiation, in order to ensure that the MTU is still sufficient to
account for the new protocol overhead.</p>
<p>In most cases you only need to call <a class="link" href="gnutls-dtls.html#gnutls-dtls-set-mtu" title="gnutls_dtls_set_mtu ()"><code class="function">gnutls_dtls_set_mtu()</code></a> with
the maximum MTU of your transport layer.</p>
<div class="refsect3">
<a name="gnutls-dtls-set-data-mtu.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>session</p></td>
<td class="parameter_description"><p>is a <a class="link" href="gnutls-gnutls.html#gnutls-session-t" title="gnutls_session_t"><span class="type">gnutls_session_t</span></a> type.</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>mtu</p></td>
<td class="parameter_description"><p>The maximum unencrypted transfer unit of the session</p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gnutls-dtls-set-data-mtu.returns"></a><h4>Returns</h4>
<p> <a class="link" href="gnutls-gnutls.html#GNUTLS-E-SUCCESS:CAPS" title="GNUTLS_E_SUCCESS"><code class="literal">GNUTLS_E_SUCCESS</code></a> (0) on success, or a negative error code.</p>
</div>
<p class="since">Since: 3.1</p>
</div>
<hr>
<div class="refsect2">
<a name="gnutls-dtls-get-timeout"></a><h3>gnutls_dtls_get_timeout ()</h3>
<pre class="programlisting">unsigned <span class="returnvalue">int</span>
gnutls_dtls_get_timeout (<em class="parameter"><code><a class="link" href="gnutls-gnutls.html#gnutls-session-t" title="gnutls_session_t"><span class="type">gnutls_session_t</span></a> session</code></em>);</pre>
<p>This function will return the milliseconds remaining
for a retransmission of the previously sent handshake
message. This function is useful when DTLS is used in
non-blocking mode, to estimate when to call <a class="link" href="gnutls-gnutls.html#gnutls-handshake" title="gnutls_handshake ()"><code class="function">gnutls_handshake()</code></a>
if no packets have been received.</p>
<div class="refsect3">
<a name="gnutls-dtls-get-timeout.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody><tr>
<td class="parameter_name"><p>session</p></td>
<td class="parameter_description"><p>is a <a class="link" href="gnutls-gnutls.html#gnutls-session-t" title="gnutls_session_t"><span class="type">gnutls_session_t</span></a> type.</p></td>
<td class="parameter_annotations"> </td>
</tr></tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gnutls-dtls-get-timeout.returns"></a><h4>Returns</h4>
<p> the remaining time in milliseconds.</p>
</div>
<p class="since">Since: 3.0</p>
</div>
<hr>
<div class="refsect2">
<a name="gnutls-dtls-cookie-send"></a><h3>gnutls_dtls_cookie_send ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span>
gnutls_dtls_cookie_send (<em class="parameter"><code><a class="link" href="gnutls-gnutls.html#gnutls-datum-t" title="gnutls_datum_t"><span class="type">gnutls_datum_t</span></a> *key</code></em>,
<em class="parameter"><code><span class="type">void</span> *client_data</code></em>,
<em class="parameter"><code><span class="type">size_t</span> client_data_size</code></em>,
<em class="parameter"><code><a class="link" href="gnutls-dtls.html#gnutls-dtls-prestate-st" title="gnutls_dtls_prestate_st"><span class="type">gnutls_dtls_prestate_st</span></a> *prestate</code></em>,
<em class="parameter"><code><a class="link" href="gnutls-gnutls.html#gnutls-transport-ptr-t" title="gnutls_transport_ptr_t"><span class="type">gnutls_transport_ptr_t</span></a> ptr</code></em>,
<em class="parameter"><code><a class="link" href="gnutls-gnutls.html#gnutls-push-func" title="gnutls_push_func ()"><span class="type">gnutls_push_func</span></a> push_func</code></em>);</pre>
<p>This function can be used to prevent denial of service
attacks to a DTLS server by requiring the client to
reply using a cookie sent by this function. That way
it can be ensured that a client we allocated resources
for (i.e. <a class="link" href="gnutls-gnutls.html#gnutls-session-t" title="gnutls_session_t"><span class="type">gnutls_session_t</span></a>) is the one that the
original incoming packet was originated from.</p>
<p>This function must be called at the first incoming packet,
prior to allocating any resources and must be succeeded
by <a class="link" href="gnutls-dtls.html#gnutls-dtls-cookie-verify" title="gnutls_dtls_cookie_verify ()"><code class="function">gnutls_dtls_cookie_verify()</code></a>.</p>
<div class="refsect3">
<a name="gnutls-dtls-cookie-send.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>key</p></td>
<td class="parameter_description"><p>is a random key to be used at cookie generation</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>client_data</p></td>
<td class="parameter_description"><p>contains data identifying the client (i.e. address)</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>client_data_size</p></td>
<td class="parameter_description"><p>The size of client's data</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>prestate</p></td>
<td class="parameter_description"><p>The previous cookie returned by <a class="link" href="gnutls-dtls.html#gnutls-dtls-cookie-verify" title="gnutls_dtls_cookie_verify ()"><code class="function">gnutls_dtls_cookie_verify()</code></a></p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>ptr</p></td>
<td class="parameter_description"><p>A transport pointer to be used by <em class="parameter"><code>push_func</code></em>
</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>push_func</p></td>
<td class="parameter_description"><p>A function that will be used to reply</p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gnutls-dtls-cookie-send.returns"></a><h4>Returns</h4>
<p> the number of bytes sent, or a negative error code. </p>
</div>
<p class="since">Since: 3.0</p>
</div>
<hr>
<div class="refsect2">
<a name="gnutls-dtls-cookie-verify"></a><h3>gnutls_dtls_cookie_verify ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span>
gnutls_dtls_cookie_verify (<em class="parameter"><code><a class="link" href="gnutls-gnutls.html#gnutls-datum-t" title="gnutls_datum_t"><span class="type">gnutls_datum_t</span></a> *key</code></em>,
<em class="parameter"><code><span class="type">void</span> *client_data</code></em>,
<em class="parameter"><code><span class="type">size_t</span> client_data_size</code></em>,
<em class="parameter"><code><span class="type">void</span> *_msg</code></em>,
<em class="parameter"><code><span class="type">size_t</span> msg_size</code></em>,
<em class="parameter"><code><a class="link" href="gnutls-dtls.html#gnutls-dtls-prestate-st" title="gnutls_dtls_prestate_st"><span class="type">gnutls_dtls_prestate_st</span></a> *prestate</code></em>);</pre>
<p>This function will verify the received message for
a valid cookie. If a valid cookie is returned then
it should be associated with the session using
<a class="link" href="gnutls-dtls.html#gnutls-dtls-prestate-set" title="gnutls_dtls_prestate_set ()"><code class="function">gnutls_dtls_prestate_set()</code></a>;</p>
<p>This function must be called after <a class="link" href="gnutls-dtls.html#gnutls-dtls-cookie-send" title="gnutls_dtls_cookie_send ()"><code class="function">gnutls_dtls_cookie_send()</code></a>.</p>
<div class="refsect3">
<a name="gnutls-dtls-cookie-verify.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>key</p></td>
<td class="parameter_description"><p>is a random key to be used at cookie generation</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>client_data</p></td>
<td class="parameter_description"><p>contains data identifying the client (i.e. address)</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>client_data_size</p></td>
<td class="parameter_description"><p>The size of client's data</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>_msg</p></td>
<td class="parameter_description"><p>An incoming message that initiates a connection.</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>msg_size</p></td>
<td class="parameter_description"><p>The size of the message.</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>prestate</p></td>
<td class="parameter_description"><p>The cookie of this client.</p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gnutls-dtls-cookie-verify.returns"></a><h4>Returns</h4>
<p> <a class="link" href="gnutls-gnutls.html#GNUTLS-E-SUCCESS:CAPS" title="GNUTLS_E_SUCCESS"><code class="literal">GNUTLS_E_SUCCESS</code></a> (0) on success, or a negative error code. </p>
</div>
<p class="since">Since: 3.0</p>
</div>
<hr>
<div class="refsect2">
<a name="gnutls-dtls-prestate-set"></a><h3>gnutls_dtls_prestate_set ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span>
gnutls_dtls_prestate_set (<em class="parameter"><code><a class="link" href="gnutls-gnutls.html#gnutls-session-t" title="gnutls_session_t"><span class="type">gnutls_session_t</span></a> session</code></em>,
<em class="parameter"><code><a class="link" href="gnutls-dtls.html#gnutls-dtls-prestate-st" title="gnutls_dtls_prestate_st"><span class="type">gnutls_dtls_prestate_st</span></a> *prestate</code></em>);</pre>
<p>This function will associate the prestate acquired by
the cookie authentication with the client, with the newly
established session.</p>
<p>This functions must be called after a successful <a class="link" href="gnutls-dtls.html#gnutls-dtls-cookie-verify" title="gnutls_dtls_cookie_verify ()"><code class="function">gnutls_dtls_cookie_verify()</code></a>
and should be succeeded by the actual DTLS handshake using <a class="link" href="gnutls-gnutls.html#gnutls-handshake" title="gnutls_handshake ()"><code class="function">gnutls_handshake()</code></a>.</p>
<div class="refsect3">
<a name="gnutls-dtls-prestate-set.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>session</p></td>
<td class="parameter_description"><p>a new session</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>prestate</p></td>
<td class="parameter_description"><p>contains the client's prestate</p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
<p class="since">Since: 3.0</p>
</div>
<hr>
<div class="refsect2">
<a name="gnutls-record-get-discarded"></a><h3>gnutls_record_get_discarded ()</h3>
<pre class="programlisting">unsigned <span class="returnvalue">int</span>
gnutls_record_get_discarded (<em class="parameter"><code><a class="link" href="gnutls-gnutls.html#gnutls-session-t" title="gnutls_session_t"><span class="type">gnutls_session_t</span></a> session</code></em>);</pre>
<p>Returns the number of discarded packets in a
DTLS connection.</p>
<div class="refsect3">
<a name="gnutls-record-get-discarded.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody><tr>
<td class="parameter_name"><p>session</p></td>
<td class="parameter_description"><p>is a <a class="link" href="gnutls-gnutls.html#gnutls-session-t" title="gnutls_session_t"><span class="type">gnutls_session_t</span></a> type.</p></td>
<td class="parameter_annotations"> </td>
</tr></tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gnutls-record-get-discarded.returns"></a><h4>Returns</h4>
<p> The number of discarded packets.</p>
</div>
<p class="since">Since: 3.0</p>
</div>
</div>
<div class="refsect1">
<a name="gnutls-dtls.other_details"></a><h2>Types and Values</h2>
<div class="refsect2">
<a name="GNUTLS-COOKIE-KEY-SIZE:CAPS"></a><h3>GNUTLS_COOKIE_KEY_SIZE</h3>
<pre class="programlisting">#define GNUTLS_COOKIE_KEY_SIZE 16
</pre>
</div>
<hr>
<div class="refsect2">
<a name="gnutls-dtls-prestate-st"></a><h3>gnutls_dtls_prestate_st</h3>
<pre class="programlisting">typedef struct {
unsigned int record_seq;
unsigned int hsk_read_seq;
unsigned int hsk_write_seq;
} gnutls_dtls_prestate_st;
</pre>
<p>DTLS cookie prestate struct. This is usually never modified by
the application, it is used to carry the cookie data between
<a class="link" href="gnutls-dtls.html#gnutls-dtls-cookie-send" title="gnutls_dtls_cookie_send ()"><code class="function">gnutls_dtls_cookie_send()</code></a>, <a class="link" href="gnutls-dtls.html#gnutls-dtls-cookie-verify" title="gnutls_dtls_cookie_verify ()"><code class="function">gnutls_dtls_cookie_verify()</code></a> and
<a class="link" href="gnutls-dtls.html#gnutls-dtls-prestate-set" title="gnutls_dtls_prestate_set ()"><code class="function">gnutls_dtls_prestate_set()</code></a>.</p>
<div class="refsect3">
<a name="gnutls-dtls-prestate-st.members"></a><h4>Members</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="300px" class="struct_members_name">
<col class="struct_members_description">
<col width="200px" class="struct_members_annotations">
</colgroup>
<tbody>
<tr>
<td class="struct_member_name"><p>unsigned <span class="type">int</span> <em class="structfield"><code><a name="gnutls-dtls-prestate-st.record-seq"></a>record_seq</code></em>;</p></td>
<td class="struct_member_description"><p>record sequence number</p></td>
<td class="struct_member_annotations"> </td>
</tr>
<tr>
<td class="struct_member_name"><p>unsigned <span class="type">int</span> <em class="structfield"><code><a name="gnutls-dtls-prestate-st.hsk-read-seq"></a>hsk_read_seq</code></em>;</p></td>
<td class="struct_member_description"><p>handshake read sequence number</p></td>
<td class="struct_member_annotations"> </td>
</tr>
<tr>
<td class="struct_member_name"><p>unsigned <span class="type">int</span> <em class="structfield"><code><a name="gnutls-dtls-prestate-st.hsk-write-seq"></a>hsk_write_seq</code></em>;</p></td>
<td class="struct_member_description"><p>handshake write sequence number</p></td>
<td class="struct_member_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
</div>
</div>
</div>
<div class="footer">
<hr>Generated by GTK-Doc V1.33.1</div>
</body>
</html>
|
